/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Collections.Generic;

namespace Lucene.Net.Search.Spans
{
    /// <summary>
    ///   <font color="#FF0000">
    /// WARNING: The status of the <b>Payloads</b> feature is experimental.
    /// The APIs introduced here might change in the future and will not be
    /// supported anymore in such a case.</font>
    ///
    /// </summary>
    public interface PayloadSpans : Spans
    {
        /// <summary>
        /// Returns the payload data for the current span.
        /// This is invalid until {@link #next()} is called for
        /// the first time.
        /// This method must not be called more than once after each call
        /// of {@link #next()}. However, payloads are loaded lazily,
        /// so if the payload data for the current position is not needed,
        /// this method may not be called at all for performance reasons.<br>
        /// <br>
        /// Note that the return type is a collection, thus the ordering should not be relied upon.
        /// <br/>
        /// <p><font color="#FF0000">
        /// WARNING: The status of the <b>Payloads</b> feature is experimental.
        /// The APIs introduced here might change in the future and will not be
        /// supported anymore in such a case.</font>
        ///
        /// @return a List of byte arrays containing the data of this payload, otherwise null if isPayloadAvailable is false
        /// @throws java.io.IOException
        /// </summary>
        // TODO: Remove warning after API has been finalized
        ICollection<byte[]> GetPayload();

        /// <summary>
        /// Checks if a payload can be loaded at this position.
        /// <p/>
        /// Payloads can only be loaded once per call to
        /// {@link #next()}.
        /// <p/>
        /// <p><font color="#FF0000">
        /// WARNING: The status of the <b>Payloads</b> feature is experimental.
        /// The APIs introduced here might change in the future and will not be
        /// supported anymore in such a case.</font>
        ///
        /// @return true if there is a payload available at this position that can be loaded
        /// </summary>
        // TODO: Remove warning after API has been finalized
        bool IsPayloadAvailable();
    }
}
